EEPROM
The Xbox EEPROM is a 256 byte non-volatile storage device which contains device-specific information. It is connected via I²C and located on address 0x54. Parts of the EEPROM are encrypted using Kernel/XboxEEPROMKey.
Contents
Contents
| Start | End | Notes |
|---|---|---|
| 0x00 | 0x13 | HMAC_SHA1 Hash |
| 0x14 | 0x1B | RC4 Encrypted Confounder ?? |
| 0x1C | 0x2B | RC4 Encrypted HDD key |
| 0x2C | 0x2F | RC4 Encrypted Region code
|
| 0x30 | 0x33 | Checksum2 - Checksum of next 44 (0x2C) bytes (0x34 - 0x5F)* |
| 0x34 | 0x3F | Xbox serial number - (ASCII chars 0x30 - 0x39 to match each digit in SN) |
| 0x40 | 0x45 | Ethernet MAC address (Microsoft Xbox - 00:50:F2:xx:xx:xx)
This is the MAC address of the Ethernet hardware, which has been issued by the IEEE. |
| 0x46 | 0x47 | Unknown Padding ? |
| 0x48 | 0x57 | Online Key ? |
| 0x58 | 0x5B | Video Standard
|
| 0x5C | 0x5F | Unknown Padding ? |
| 0x60 | 0x63 | Checksum3 - Checksum of the next 92 (0x5C) bytes (0x64 - 0xBF)* |
| 0x64 | 0x67 | Zone Bias - Offset in # minutes to subtract from GMT time
(e.g., for GMT-06 Central; 6hr = 360min = 0x00000168) |
| 0x68 | 0x6B | Standard Timezone Name: 4 characters, NULL fill remainder if shorter (e.g., CST\0, ACST) |
| 0x6C | 0x6F | Daylight Timezone Name: 4 characters, NULL fill remainder if shorter (e.g., CDT\0, ACDT) |
| 0x70 | 0x77 | Unknown Padding ? |
| 0x78 | 0x7B | Standard Time Starts 10-05-00-02 (Month-Day-DayOfWeek-Hour) |
| 0x7C | 0x7F | Daylight Savings Time Starts 04-01-00-02 (Month-Day-DayOfWeek-Hour) |
| 0x80 | 0x87 | Unknown Padding ? |
| 0x88 | 0x8B | Standard Timezone Bias; if not DST, 0 (0x00000000) minute time adjust |
| 0x8C | 0x8F | Daylight Savings Time Bias; if DST, -60 (0xFFFFFFC4) minute time adjust |
| 0x90 | 0x93 | Language ID (0 = not set)
|
| 0x94 | 0x97 | Video Settings
|
| 0x98 | 0x9B | Audio Settings
|
| 0x9C | 0x9F | Games Parental Control (0 = Max rating)
|
| 0xA0 | 0xA3 | Parental Control Passcode; 4 button sequence (each key stored in a nibble)
Note:
|
| 0xA4 | 0xA7 | Movies Parental Control (0 = Max rating)
|
| 0xA8 | 0xAB | XBOX Live IP Address.. |
| 0xAC | 0xAF | XBOX Live DNS Server.. |
| 0xB0 | 0xB3 | XBOX Live Gateway Address.. |
| 0xB4 | 0xB7 | XBOX Live Subnet Mask.. |
| 0xB8 | 0xBB | Other XBLive settings ? |
| 0xBC | 0xBF | DVD Playback Kit Zone
|
| 0xC0 | 0xFF | Unknown Codes / History ? do not change any values in this range |
Note: Info in above table comes from XKUtils XKEEPROM.h.
*Configmagic-FINAL-1.6 uses the wrong size when computing Checksum2 (40 instead of 44 bytes) and Checksum3 (96 instead of 92 bytes). Checksum2 value computed was correct only because the extra 4 bytes not used in the CRC computation were all 0's which does not change the CRC value. However, a similiar problem with computation of Checksum3 is present. The CRC computed for v1.6 Xbox's is incorrect as the 4 extra bytes are not 0's as on earlier versions.
Reading/Writing the EEPROM
Software Method
This is the easiest way to dump an Xbox EEPROM. Use your alternative dashboard to dump the EEPROM to a file and download it over FTP.
Hardware Method
If you cannot dump the EEPROM using software, you can dump it using hardware. You have several options: use an I2C host adapter (see here or here), build an I2C-Serial cable, or use a device like a RaspberryPi which has an I2C interface. Connect SDA/SCL/ground to the LPC pinout on the board. See here for pinout information. Then use the corresponding software to read/write the EEPROM.
The HMAC HDD Key
The HMAC HDD Key is generated[FIXME] out of the first 48 bytes[FIXME]. This section has been identified clearly[FIXME].
Checksum Algorithm
Checksum2 and Checksum3 values can be calculated by running the following code snippet over the area the checksum covers:
/* The EepromCRC algorithm was obtained from the XKUtils 0.2 source released by
* TeamAssembly under the GNU GPL.
* Specifically, from XKCRC.cpp
*
* Rewritten to ANSI C by David Pye (dmp@davidmpye.dyndns.org)
*
* Adapted for XboxDevWiki
*/
uint32_t EepromCRC(unsigned char *data, long dataLen) {
// Initialize result to zero
uint8_t crc[4] = { 0x00, 0x00, 0x00, 0x00 };
//Circle shift input data one byte right
unsigned char* CRC_Data = (unsigned char *)malloc(dataLen + 4);
memset(CRC_Data, 0x00, dataLen + 4);
memcpy(CRC_Data + 0x01 , data, dataLen - 1);
memcpy(CRC_Data, data + dataLen - 1, 0x01);
// Calculate checksum
for (unsigned int i = 0; i < 4; i++) {
unsigned short CRCPosVal = 0xFFFF;
for (unsigned long l = i; l < dataLen; l += 4) {
CRCPosVal -= *(unsigned short*)(&CRC_Data[l]);
}
CRCPosVal &= 0xFF00;
crc[i] = (unsigned char) (CRCPosVal >> 8);
}
free(CRC_Data);
return *(uint32_t*)&checksum;
}
Read Checksum Algorithm
When the Xbox reads from the FACTORY_SETTINGS or the USER_SETTINGS section of the EEPROM, this algorithm is ran over the entire section accessed (including the CRC checksum mentioned above) to ensure that the data is valid. If the result of the checksum algorithm does not equal 0xFFFFFFFF, STATUS_DEVICE_DATA_ERROR is returned from the Kernel.
static uint32_t eeprom_section_checksum(
const uint32_t* section_data,
uint32_t section_data_length
)
{
const uint32_t bitmask = 0xFFFFFFFF;
uint64_t checksum = 0;
uint32_t carry_count = 0;
// Process the data in 32 bit steps
for(unsigned int i = 0; i < section_data_length / 4; i++) {
checksum += *section_data;
if(checksum > bitmask) {
carry_count++;
checksum &= bitmask;
}
section_data++;
}
checksum += carry_count;
if(checksum > bitmask) {
checksum += 1;
}
return (uint32_t)(checksum & bitmask);
}
